The present invention relates to a reactor head for a monolithic co-current or countercurrent reactor.
Co-current or countercurrent reactors are described in the previously unpublished European Patent Application EP 0 752 390 A1.
A co-current or countercurrent reactor has the form of a cylinder of any cross-sectional area and is traversed by parallel flow ducts which connect the two end faces of the reactor to one another. Such a device is generally referred to as a honeycomb system. It may be manufactured from metal or ceramic. The cross-section of the flow ducts may be triangular, square, rectangular, hexagonal or of some other shape. The number of flow ducts in relation to the cross-sectional area is referred to as the cell density.
EP 0 752 390 A1 describes such a honeycomb system for the production of hydrocyanic acid by the reaction of methane and ammonia in the presence of a suitable catalyst. The reaction of methane and ammonia is an endothermic reaction and is carried out at temperatures of 1000.degree. C. to 1350.degree. C.
According to EP 0 752 390 A1, the flow ducts of the honeycomb system are subdivided into heating ducts and reaction ducts. Heating ducts and reaction ducts are distributed in a complementary pattern over the cross-section of the honeycomb system. The pattern of distribution of the ducts may in principle be chosen at random, but an arrangement of alternating heating ducts and reaction ducts in layers or rows has proved to be successful. The reaction mixture of methane and ammonia is passed through the reaction ducts. A fuel gas/air mixture is passed through the heating ducts in a co-current or countercurrent direction to the reaction mixture and is introduced into the ducts for the combustion. Because of the immediate proximity of the heating ducts and the reaction ducts, the heat liberated during combustion is efficiently transferred to the reactants. In order to carry out the catalytic conversion, the inside walls of the reaction ducts are coated with a catalyst for the catalytic conversion.
The combustion in the heating ducts is ignited by heating wires introduced into the ducts. The ignition of the combustion in the heating ducts may however also be effected catalytically. To this end the surfaces of the inside walls of the heating ducts can be coated with a catalyst for the catalytic combustion.
A fundamental problem of the reactor concept as presented heretofore is the feed of the reaction gases and of the combustion gases into each of the ducts assigned to them. One possibility of feeding these gases into the ducts is disclosed in U.S. Pat. No. 4,271,110 for the case of an indirect heat exchanger in the form of a honeycomb body. On the assumption that heating ducts and reaction ducts are arranged alternately in layers or rows, the feed and removal of the gases may be effected according to the above U.S. patent in the following manner:
The fuel gas/air mixture is passed to one end face of the reactor with the aid of a conical connecting pipe attached to the end face. The reaction mixture is passed to the second end face in a corresponding manner. The flow ducts are closed in the axial direction on the end face opposite to the respective inlet end face in order to prevent mixing of the two gaseous flows. The withdrawal of the gas flows is effected through the lateral faces of the reactor. To this end, starting from one lateral face, the reactor has incorporated within it openings which connect all the ducts of one layer with one another. The gas flows issuing from the individual layers can be combined by attaching a connecting gas pipe to the lateral face of the reactor.
This solution to the problem of introducing the gases is unsatisfactory on account of its limited flexibility, as it can be applied only to reactors having heating ducts and reaction ducts arranged in layers. It has moreover been found that the stability of the combustion in the ducts is unsatisfactory.
It is accordingly an object of the present invention to overcome the shortcomings and drawbacks of prior known co-current and countercurrent reactors.
A further object of this invention is to enable introduction of the heating gases and reaction gases into the appropriate ducts of co-current and countercurrent reactors; even though heating ducts and reaction ducts may be arranged in any pattern over the cross-section of the reactor.